The function of traditional electronic speed regulator and mechanical speed reducer can only be used alone, so that electromechanical linkage control cannot be realized. The traditional electronic speed regulator only regulates the speed of power source. The power has damping difference in the process of transmission. The stability problem of load real-time operation cannot be directly solved by the electronic speed regulator. The traditional mechanical speed reducer has single function and cannot randomly control and regulate speed ratio when used, so that the use function of the product is limited greatly. The existing precise speed reducer for intelligent devices and supporting for servo motors has higher requirement for product design, material and technology and very high market application cost, so as to go against popularization and promotion. Additionally, the production technology in developed countries has become mature so far, and it is very difficult to break through the technical level of the original product except for innovative design ideas. Due to the limit of the traditional transmission technology, the product like intelligent precise speed regulator-reducer capable of realizing the mechatronic function has not been discovered yet in the current global market of power transmission and control technology.
Magneto-rheological fluid made of a novel phase change material is magnetic particle suspension fluid mixed with minute (micron- or even nanometer-level) soft magnetic particles with high permeability and low magnetic retardation. Suspended iron particles freely move along with the fluid in the absence of magnetic field, but these suspended iron particles are mutually attracted in the presence of magnetic field to form a cluster of chain structures from one pole of the magnetic field to the other pole thereof. At this time, the magneto-rheological fluid is turned into a plastic body or a viscoelastic body with a certain yield shear stress at the moment of millisecond. When the current in the a magnetic field coil is changed to obtain the magnetic field with different strength, the yield shear stress of the magneto-rheological fluid is also changed, that is to say, an anti-shearing force is very high under the action of the strong magnetic field to show the fluid feature of high viscosity and low fluidity. The feature of low viscosity is shown under the condition of zero magnetic field, and the shearing yield strength and the magnetic field strength (or current strength) have a stable corresponding relation. The continuous variability of the damping force can be realized due to such rheology controllability of the magneto-rheological fluid so as to achieve the active control on clutch brake of the power transmission.